diff --git a/demo-sample.mp4 b/demo-sample.mp4
new file mode 100644
index 0000000..c600153
Binary files /dev/null and b/demo-sample.mp4 differ
diff --git a/index.html b/index.html
index d257cbf..b198830 100644
--- a/index.html
+++ b/index.html
@@ -1206,6 +1206,8 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "write a note…":"escribe una nota…",
     "remove":"quitar",
     "to run":"para ejecutar",
+    "to run for real":"para ejecutar de verdad",
+    "The sample results are canned, so this run isn’t billed. This is what running the graph on your own key costs.":"Los resultados de muestra son pregrabados, así que esta ejecución no se cobra. Esto es lo que cuesta ejecutar el flujo con tu propia clave.",
     "Estimated cost to ▶ Run all — {n} paid node":"Coste estimado de ▶ Ejecutar todo — {n} nodo de pago",
     "Estimated cost to ▶ Run all — {n} paid nodes":"Coste estimado de ▶ Ejecutar todo — {n} nodos de pago",
     ", plus {n} with no listed price":", más {n} sin precio listado",
@@ -1254,6 +1256,7 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "turns this into a shareable mini app.":"lo convierte en una mini app compartible.",
     "Sample preview":"Vista previa de muestra",
     "your edits aren’t reflected yet — results below are still the starter sample. Sign in to run YOUR prompt for real, pay-per-use on your own key.":"tus cambios aún no se reflejan — abajo sigue la muestra del ejemplo inicial. Inicia sesión para ejecutar TU prompt de verdad, pago por uso con tu propia clave.",
+    "the clip below is a canned example of what Image→Video makes, not your prompt. Sign in to run YOUR graph for real, pay-per-use on your own key.":"el clip de abajo es un ejemplo enlatado de lo que hace Imagen→Vídeo, no tu prompt. Inicia sesión para ejecutar TU flujo de verdad, pago por uso con tu propia clave.",
     "This is your app.":"Esta es tu app.",
     "restyles it;":"la rediseña;",
     "returns to the graph and keeps this app bound.":"vuelve al grafo y mantiene esta app vinculada.",
@@ -1445,7 +1448,8 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "results below are canned examples, not live AI — sign in to run it for real, pay-per-use on your own key.":"los resultados de abajo son ejemplos pregrabados, no IA en vivo — inicia sesión para ejecutarlo de verdad, pago por uso con tu propia clave.",
     "sample result — sign in to run it for real":"resultado de muestra — inicia sesión para ejecutarlo de verdad",
     "Run to make your own":"Ejecuta para crear el tuyo",
-    "samples cover text and images only — sign in to run this node for real":"las muestras solo cubren texto e imágenes — inicia sesión para ejecutar este nodo de verdad",
+    "the sample doesn't cover this node — sign in to run it for real":"la muestra no cubre este nodo — inicia sesión para ejecutarlo de verdad",
+    "the sample clip couldn't load — sign in to run this node for real":"no se pudo cargar el clip de muestra — inicia sesión para ejecutar este nodo de verdad",
     "more sign-in options":"más opciones de inicio de sesión",
     "sign out":"cerrar sesión",
     "checking…":"comprobando…",
@@ -1721,6 +1725,8 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "write a note…":"écrire une note…",
     "remove":"retirer",
     "to run":"pour exécuter",
+    "to run for real":"pour exécuter vraiment",
+    "The sample results are canned, so this run isn’t billed. This is what running the graph on your own key costs.":"Les résultats d’exemple sont préenregistrés, donc cette exécution n’est pas facturée. Voici ce que coûte l’exécution du graphe avec votre propre clé.",
     "Estimated cost to ▶ Run all — {n} paid node":"Coût estimé de ▶ Tout exécuter — {n} nœud payant",
     "Estimated cost to ▶ Run all — {n} paid nodes":"Coût estimé de ▶ Tout exécuter — {n} nœuds payants",
     ", plus {n} with no listed price":", plus {n} sans prix affiché",
@@ -1775,6 +1781,7 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "turns this into a shareable mini app.":"en fait une mini app partageable.",
     "Sample preview":"Aperçu d’exemple",
     "your edits aren’t reflected yet — results below are still the starter sample. Sign in to run YOUR prompt for real, pay-per-use on your own key.":"vos modifications ne sont pas encore prises en compte — les résultats ci-dessous restent l’exemple de départ. Connectez-vous pour exécuter VOTRE prompt pour de vrai, paiement à l’usage avec votre clé.",
+    "the clip below is a canned example of what Image→Video makes, not your prompt. Sign in to run YOUR graph for real, pay-per-use on your own key.":"le clip ci-dessous est un exemple préenregistré de ce que fait Image→Vidéo, pas votre prompt. Connectez-vous pour exécuter VOTRE graphe pour de vrai, paiement à l’usage avec votre clé.",
     "This is your app.":"Voici votre app.",
     "restyles it;":"la restyle ;",
     "returns to the graph and keeps this app bound.":"revient au graphe et garde cette app liée.",
@@ -1960,7 +1967,8 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "results below are canned examples, not live AI — sign in to run it for real, pay-per-use on your own key.":"les résultats ci-dessous sont des exemples préenregistrés, pas de l’IA en direct — connectez-vous pour l’exécuter vraiment, paiement à l’usage avec votre propre clé.",
     "sample result — sign in to run it for real":"résultat d’exemple — connectez-vous pour l’exécuter vraiment",
     "Run to make your own":"Lancez pour créer le vôtre",
-    "samples cover text and images only — sign in to run this node for real":"les exemples ne couvrent que le texte et les images — connectez-vous pour vraiment exécuter ce nœud",
+    "the sample doesn't cover this node — sign in to run it for real":"l’exemple ne couvre pas ce nœud — connectez-vous pour l’exécuter pour de vrai",
+    "the sample clip couldn't load — sign in to run this node for real":"le clip d’exemple n’a pas pu être chargé — connectez-vous pour exécuter ce nœud pour de vrai",
     "more sign-in options":"autres options de connexion",
     "sign out":"se déconnecter",
     "checking…":"vérification…",
@@ -2236,6 +2244,8 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "write a note…":"Notiz schreiben…",
     "remove":"entfernen",
     "to run":"zum Ausführen",
+    "to run for real":"um wirklich auszuführen",
+    "The sample results are canned, so this run isn’t billed. This is what running the graph on your own key costs.":"Die Beispielergebnisse sind vorbereitet, deshalb wird dieser Lauf nicht berechnet. So viel kostet es, den Graphen mit eigenem Schlüssel auszuführen.",
     "Estimated cost to ▶ Run all — {n} paid node":"Geschätzte Kosten für ▶ Alles ausführen — {n} kostenpflichtiger Node",
     "Estimated cost to ▶ Run all — {n} paid nodes":"Geschätzte Kosten für ▶ Alles ausführen — {n} kostenpflichtige Nodes",
     ", plus {n} with no listed price":", plus {n} ohne gelisteten Preis",
@@ -2286,6 +2296,7 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "turns this into a shareable mini app.":"macht daraus eine teilbare Mini-App.",
     "Sample preview":"Beispiel-Vorschau",
     "your edits aren’t reflected yet — results below are still the starter sample. Sign in to run YOUR prompt for real, pay-per-use on your own key.":"deine Änderungen sind noch nicht drin — unten ist noch das Starter-Beispiel. Melde dich an, um DEINEN Prompt wirklich auszuführen, Bezahlung pro Nutzung mit eigenem Schlüssel.",
+    "the clip below is a canned example of what Image→Video makes, not your prompt. Sign in to run YOUR graph for real, pay-per-use on your own key.":"der Clip unten ist ein vorgefertigtes Beispiel dafür, was Bild→Video macht, nicht dein Prompt. Melde dich an, um DEINEN Graphen wirklich auszuführen, Bezahlung pro Nutzung mit eigenem Schlüssel.",
     "This is your app.":"Das ist deine App.",
     "restyles it;":"gestaltet sie um;",
     "returns to the graph and keeps this app bound.":"kehrt zum Graph zurück und behält diese App gebunden.",
@@ -2475,7 +2486,8 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "results below are canned examples, not live AI — sign in to run it for real, pay-per-use on your own key.":"die Ergebnisse unten sind vorbereitete Beispiele, keine echte KI — melde dich an, um es wirklich auszuführen, Bezahlung pro Nutzung mit eigenem Schlüssel.",
     "sample result — sign in to run it for real":"Beispielergebnis — melde dich an, um es wirklich auszuführen",
     "Run to make your own":"Starte, um dein eigenes zu erstellen",
-    "samples cover text and images only — sign in to run this node for real":"Beispiele decken nur Text und Bilder ab — melde dich an, um diesen Knoten wirklich auszuführen",
+    "the sample doesn't cover this node — sign in to run it for real":"das Beispiel deckt diesen Knoten nicht ab — melde dich an, um ihn wirklich auszuführen",
+    "the sample clip couldn't load — sign in to run this node for real":"der Beispielclip konnte nicht geladen werden — melde dich an, um diesen Knoten wirklich auszuführen",
     "more sign-in options":"weitere Anmeldeoptionen",
     "sign out":"abmelden",
     "checking…":"wird geprüft…",
@@ -2751,6 +2763,8 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "write a note…":"escreva uma nota…",
     "remove":"remover",
     "to run":"para executar",
+    "to run for real":"para executar de verdade",
+    "The sample results are canned, so this run isn’t billed. This is what running the graph on your own key costs.":"Os resultados de amostra são pré-gravados, por isso esta execução não é cobrada. Isto é o que custa executar o fluxo com a sua própria chave.",
     "Estimated cost to ▶ Run all — {n} paid node":"Custo estimado de ▶ Executar tudo — {n} nó pago",
     "Estimated cost to ▶ Run all — {n} paid nodes":"Custo estimado de ▶ Executar tudo — {n} nós pagos",
     ", plus {n} with no listed price":", mais {n} sem preço listado",
@@ -2800,6 +2814,7 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "turns this into a shareable mini app.":"transforma isto numa mini app partilhável.",
     "Sample preview":"Pré-visualização de amostra",
     "your edits aren’t reflected yet — results below are still the starter sample. Sign in to run YOUR prompt for real, pay-per-use on your own key.":"as suas edições ainda não se reflectem — abaixo continua a amostra inicial. Entre para executar O SEU prompt de verdade, pagamento por uso com a sua própria chave.",
+    "the clip below is a canned example of what Image→Video makes, not your prompt. Sign in to run YOUR graph for real, pay-per-use on your own key.":"o clipe abaixo é um exemplo pré-gravado do que Imagem→Vídeo faz, não o seu prompt. Entre para executar O SEU fluxo de verdade, pagamento por uso com a sua própria chave.",
     "This is your app.":"Esta é a sua app.",
     "restyles it;":"redesenha-a;",
     "returns to the graph and keeps this app bound.":"volta ao grafo e mantém esta app ligada.",
@@ -2990,7 +3005,8 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "results below are canned examples, not live AI — sign in to run it for real, pay-per-use on your own key.":"os resultados abaixo são exemplos pré-gravados, não IA ao vivo — entre para executar de verdade, pagamento por uso com a sua própria chave.",
     "sample result — sign in to run it for real":"resultado de amostra — entre para executar de verdade",
     "Run to make your own":"Execute para criar o seu",
-    "samples cover text and images only — sign in to run this node for real":"as amostras cobrem apenas texto e imagens — entre para executar este nó de verdade",
+    "the sample doesn't cover this node — sign in to run it for real":"a amostra não cobre este nó — entre para executá-lo de verdade",
+    "the sample clip couldn't load — sign in to run this node for real":"não foi possível carregar o clipe de amostra — entre para executar este nó de verdade",
     "more sign-in options":"mais opções de login",
     "sign out":"sair",
     "checking…":"verificando…",
@@ -3266,6 +3282,8 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "write a note…":"メモを書く…",
     "remove":"削除",
     "to run":"で実行",
+    "to run for real":"を実際に実行",
+    "The sample results are canned, so this run isn’t billed. This is what running the graph on your own key costs.":"サンプル結果はあらかじめ用意されたものなので、この実行は課金されません。自分のキーでこのグラフを実行するとこの費用がかかります。",
     "Estimated cost to ▶ Run all — {n} paid node":"▶ すべて実行の推定コスト — 有料ノード {n} 個",
     "Estimated cost to ▶ Run all — {n} paid nodes":"▶ すべて実行の推定コスト — 有料ノード {n} 個",
     ", plus {n} with no listed price":"、ほかに価格未掲載 {n} 個",
@@ -3311,6 +3329,7 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "turns this into a shareable mini app.":"で共有できるミニアプリにします。",
     "Sample preview":"サンプルプレビュー",
     "your edits aren’t reflected yet — results below are still the starter sample. Sign in to run YOUR prompt for real, pay-per-use on your own key.":"編集はまだ反映されていません — 下はスターターのサンプルのままです。サインインすると自分のプロンプトを本当に実行できます(自分のキーで従量課金)。",
+    "the clip below is a canned example of what Image→Video makes, not your prompt. Sign in to run YOUR graph for real, pay-per-use on your own key.":"下のクリップは画像→動画の出力例(録画済み)で、あなたのプロンプトの結果ではありません。サインインすると自分のグラフを本当に実行できます(自分のキーで従量課金)。",
     "This is your app.":"これがあなたのアプリです。",
     "restyles it;":"見た目を変え、",
     "returns to the graph and keeps this app bound.":"でグラフに戻り、このアプリの紐づけは保たれます。",
@@ -3505,7 +3524,8 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     "results below are canned examples, not live AI — sign in to run it for real, pay-per-use on your own key.":"以下の結果はあらかじめ用意されたサンプルで、実際のAIではありません — サインインすると自分のキーで本当に実行できます(従量課金)。",
     "sample result — sign in to run it for real":"サンプル結果 — サインインすると本当に実行できます",
     "Run to make your own":"実行して自分だけの作品を",
-    "samples cover text and images only — sign in to run this node for real":"サンプルはテキストと画像のみ対応 — サインインするとこのノードを本当に実行できます",
+    "the sample doesn't cover this node — sign in to run it for real":"このノードはサンプルの対象外です — サインインすると本当に実行できます",
+    "the sample clip couldn't load — sign in to run this node for real":"サンプル動画を読み込めませんでした — サインインするとこのノードを本当に実行できます",
     "more sign-in options":"その他のサインイン方法",
     "sign out":"サインアウト",
     "checking…":"確認中…",
@@ -5748,8 +5768,10 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
   return { usd, priced, unpriced, exact };
 }
 const fmtUsd = (v)=> v>=0.01 ? `$${v.toFixed(2)}` : v>0 ? `<$0.01` : `$0.00`;
-// True while a signed-out visitor can still free-sample Run (pristine starter OR same topology with
-// only field tweaks — see demoMode). We hide the price so the first click reads as "just try it".
+// True while a signed-out visitor can still free-sample Run (pristine starter, same topology with
+// only field tweaks, or the covered Image→Video extension — see demoMode). The run-cost chip stays
+// VISIBLE here, relabelled "to run for real": this click is not billed, but the figure is exactly
+// what the visitor wants before they sign in. See refreshRunEstimate.
 function inDemoRun(){ return !getKey() && !!demoMode(); }
 // Paint a faded, captioned teaser of what ▶ Run produces into an output node's result area, so a
 // first-run visitor sees the reward at rest — not just the wired-up apparatus. View-only: never sets
@@ -5782,14 +5804,24 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
 function refreshRunEstimate(){
   refreshDemoGhosts();                             // demo teaser shares this function's three trigger sites
   const el = $("runest"); if(!el) return;
-  if(inDemoRun()){ el.hidden = true; return; }   // free sample run → no price talk yet
+  // A demo run is not billed, but the chip STAYS UP — relabelled so it clearly prices the real
+  // run, not this click. Hiding it used to look harmless (nothing is charged, so nothing is
+  // concealed) and is not: the one thing a signed-out visitor can add to the starter is an
+  // Image→Video node, the priciest node on the canvas, and the cost figure vanished at exactly
+  // the moment it became worth reading. A price that disappears when it gets big reads as a dark
+  // pattern however it got there, so we show it and say which run it is for.
+  const demo = inDemoRun();
   const { usd, priced, unpriced, exact } = workflowCost();
   if(!priced){ el.hidden = true; return; }        // nothing priced to run → hide the chip entirely
   el.hidden = false;
-  el.innerHTML = `<span class="rn-run" aria-hidden="true">▶</span>${exact?"":"~"}<b>${fmtUsd(usd)}</b>&nbsp;${esc(t("to run"))}`;
-  el.title = t(priced>1 ? "Estimated cost to ▶ Run all — {n} paid nodes" : "Estimated cost to ▶ Run all — {n} paid node").replace("{n}",()=>priced)
-    + (unpriced ? t(", plus {n} with no listed price").replace("{n}",()=>unpriced) : "")
-    + (exact ? "." : "." + "\n" + t("Video, text & audio are estimates: the real bill depends on clip length, tokens and characters."));
+  const amt = `<span class="rn-run" aria-hidden="true">▶</span>${exact?"":"~"}<b>${fmtUsd(usd)}</b>&nbsp;`;
+  el.innerHTML = demo ? amt + `${esc(t("to run for real"))}` : amt + `${esc(t("to run"))}`;
+  el.title = (demo
+      ? t("The sample results are canned, so this run isn’t billed. This is what running the graph on your own key costs.")
+      : t(priced>1 ? "Estimated cost to ▶ Run all — {n} paid nodes" : "Estimated cost to ▶ Run all — {n} paid node").replace("{n}",()=>priced)
+        + (unpriced ? t(", plus {n} with no listed price").replace("{n}",()=>unpriced) : "")
+        + ".")
+    + (exact ? "" : "\n" + t("Video, text & audio are estimates: the real bill depends on clip length, tokens and characters."));
 }
 function refreshAllPrices(){ graph.nodes.forEach(n=>{ updateNodePrice(n); refreshDims(n); refreshAudioParams(n); refreshTranscribeLang(n); refreshCivitParams(n); refreshLoraParams(n); refreshModelOpts(n); refreshLlmOpts(n); refreshImageInputs(n); refreshAudioInputs(n); refreshEndFrameInput(n); refreshRefInputs(n); refreshRefHint(n); backfillModel(n); }); refreshRunEstimate(); refreshPromptCaps(); }   // refreshPromptCaps: audio caps ARE catalog metadata (max_chars) and every note names the model, so both are blank until the catalog lands. refreshLlmOpts: reconcile knobs kept during a catalog miss (#311) once real capability flags exist; the dynamic port families (img/audio/endframe/ref) are catalog-gated too — without them a cold-cache boot (shared link, cleared storage) paints a saved ref-model graph portless until a reload
 function backfillModel(n){   // once a catalog arrives, give model nodes a sensible default if none chosen yet
@@ -8913,7 +8945,16 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
      demoStarterSig   — full content (fields + types + links); exact match → sample as-is
      demoStarterShape — topology only (ids/types/links); same shape with field tweaks still
                         free-samples, but the pill warns that canned results ignore the edit.
-   Topology changes, share links, examples, etc. still get the honest sign-in wall. */
+
+   Plus ONE covered extension: the starter with a 📽️ Image→Video node hung off the image
+   output (see demoVideoNode). Video is the thing people come here to see, and a curious
+   signed-out visitor who wires one up used to lose the demo entirely — the topology no longer
+   matched, so the Run click ended on the sign-in wall instead of the wow. That shape now serves
+   demo-sample.mp4, rendered once from the shipped demo-sample.jpg by a real image→video model
+   (scripts/gen-demo-clip.mjs records the model and reproduces the file).
+
+   Everything else — other topologies, share links, examples — still gets the honest sign-in
+   wall, and every canned result carries the sample badge. */
 let demoStarterSig = null;
 let demoStarterShape = null;
 // Topology fingerprint (ids + types + wire ends). Field edits don't change it; add/remove/rewire do.
@@ -8924,11 +8965,33 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
     links: (g.links||[]).map(l=>({ f:l.from, t:l.to })),
   });
 }
-// 'exact' | 'shape' | null — whether a signed-out Run may free-sample this canvas.
+// The ONE covered extension of the starter: an 📽️ Image→Video node fed by the image node's
+// output, with nothing downstream of it. Returns that node, or null when the canvas is anything
+// else. Structural on purpose (not a second baked signature): the appended node's id depends on
+// how many nodes the visitor added and removed first, so an id-for-id comparison would miss the
+// very path we are covering.
+function demoVideoNode(g){
+  if(!demoStarterShape) return null;
+  g = g || graph;
+  const nodes = g.nodes || [], links = g.links || [];
+  const vids = nodes.filter(n=> n.type === "ivideo");
+  if(vids.length !== 1) return null;
+  const v = vids[0];
+  if(links.some(l=> l.from.node === v.id)) return null;                  // nothing downstream — we can only can ITS output
+  const into = links.filter(l=> l.to.node === v.id);
+  if(into.length !== 1 || into[0].to.port !== "image") return null;      // exactly one wire, into the image port (an end-frame morph is not covered)
+  const src = nodes.find(n=> n.id === into[0].from.node);
+  if(!src || src.type !== "image" || into[0].from.port !== "image") return null;
+  // ...and the rest of the canvas is still the starter, wire for wire.
+  const rest = { nodes: nodes.filter(n=> n.id !== v.id), links: links.filter(l=> l.to.node !== v.id) };
+  return demoShapeSig(rest) === demoStarterShape ? v : null;
+}
+// 'exact' | 'shape' | 'video' | null — whether a signed-out Run may free-sample this canvas.
 function demoMode(){
   if(!demoStarterShape) return null;
   if(demoStarterSig && appHandoffSig() === demoStarterSig) return "exact";
   if(demoShapeSig() === demoStarterShape) return "shape";
+  if(demoVideoNode()) return "video";
   return null;
 }
 const DEMO_LLM_TEXT = "A cozy, intimate ramen shop on a rainy night, viewed from the quiet street looking slightly through the steamed glass window. Warm, glowing amber light spills out onto the wet pavement, contrasting beautifully with the cool, moody blue and teal tones of the rainy city. Inside, a lone patron in a yellow raincoat sits at a wooden bar, steam rising in thick, inviting plumes from a large bowl of rich tonkotsu ramen. Paper lanterns emit a soft, nostalgic luminescence over wooden interiors. Puddles on the cobblestone street reflect the vibrant shop signs and passing neon city lights. Cinematic lighting, photorealistic, 8k resolution, ultra-detailed, comforting and atmospheric mood, anime-inspired realism.";
@@ -8944,6 +9007,25 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
   }catch(_){ _demoImgUrl = DEMO_IMG_FALLBACK; }
   return _demoImgUrl;
 }
+// The clip half of the sample, same contract as demoImage(): shipped next to the page and read
+// into a data URL, so ⬇ save / ↗ open behave exactly like a real result.
+// No stand-in here, unlike DEMO_IMG_FALLBACK: a <video> cannot render a labelled SVG, and a
+// placeholder clip would be us faking what the model makes. So a missing/blocked file resolves to
+// null and the caller falls back to the sign-in wall — never a broken player.
+// The content-type test is load-bearing: a static host answers an absent path with the SPA's
+// index.html at status 200, which would otherwise become a data:text/html "video".
+let _demoClipUrl;
+async function demoClip(){
+  if(_demoClipUrl !== undefined) return _demoClipUrl;
+  try{
+    const r = await fetch("demo-sample.mp4");
+    if(!r.ok) throw new Error(String(r.status));
+    const blob = await r.blob();
+    if(!blob.size || !/^video\//.test(blob.type)) throw new Error("not a clip");
+    _demoClipUrl = await new Promise((res, rej)=>{ const fr = new FileReader(); fr.onload = ()=> res(fr.result); fr.onerror = rej; fr.readAsDataURL(blob); });
+  }catch(_){ _demoClipUrl = null; }
+  return _demoClipUrl;
+}
 // A believable pause that still honors ■ Stop (rejects as AbortError, same as a real fetch).
 const demoPause = (ms)=> new Promise((res, rej)=>{
   const s = runSignal();
@@ -8951,14 +9033,24 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
   const id = setTimeout(res, ms);
   s?.addEventListener("abort", ()=>{ clearTimeout(id); rej(new DOMException("Aborted", "AbortError")); }, { once:true });
 });
-const demoDeny = async ()=>{ await demoPause(600); throw new Error("samples cover text and images only — sign in to run this node for real"); };
+const demoDeny = async ()=>{ await demoPause(600); throw new Error(t("the sample doesn't cover this node — sign in to run it for real")); };
 const DEMO_CTX = { ...CTX, demo:true,
   async genChat(){ await demoPause(1400 + Math.random()*1200); return DEMO_LLM_TEXT; },
   async genImage(prompt, model, size, imageDataUrl, maskDataUrl, extra, opts){
     const [url] = await Promise.all([demoImage(), demoPause(2800 + Math.random()*1600)]);
     return (opts && opts.multi) ? [url] : url;
   },
-  genVideo: demoDeny, genAudio: demoDeny, transcribe: demoDeny,
+  // Only the one covered Image→Video node gets the clip. opts.runKey is the node id (every video
+  // runner sets it), so a 🎬 Text→Video or 🎞️ Video-edit node — or a second video node the shape
+  // check already rejected — still lands on the wall instead of a result that is not about it.
+  async genVideo(model, prompt, opts, imageDataUrl, onProgress){
+    const v = demoVideoNode();
+    if(!v || !opts || opts.runKey !== v.id) return demoDeny();
+    const [url] = await Promise.all([demoClip(), demoPause(4200 + Math.random()*2400)]);   // longer than the image beat: rendering a clip really does take longer
+    if(!url) throw new Error(t("the sample clip couldn't load — sign in to run this node for real"));
+    return url;
+  },
+  genAudio: demoDeny, transcribe: demoDeny,
 };
 // "loading sample…" — honest running-state text for a demo node (t() is free here, unshadowed).
 function demoRunLabel(){ return t("loading sample…"); }
@@ -8968,7 +9060,8 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
   if(!r || !r.classList.contains("show") || r.querySelector(".demobadge")) return;   // pass-through nodes (text/media inputs) show no result — nothing to label
   r.insertAdjacentHTML("beforeend", `<div class="demobadge">✨ ${esc(t("sample result — sign in to run it for real"))}</div>`);
 }
-// mode: 'exact' (pristine starter) | 'shape' (same topology, field tweaks) | null (not sampleable).
+// mode: 'exact' (pristine starter) | 'shape' (same topology, field tweaks) | 'video' (starter + an
+// appended Image→Video node) | null (not sampleable).
 // Legacy booleans still work: true → wall, false → exact sample (older tests / call sites).
 function openDemoPop(mode){
   if(mode === true) mode = null;
@@ -8982,6 +9075,10 @@ <h3 class="rf-title" id="refueltitle">Top up to keep running</h3>
       txt.innerHTML = `<b>${esc(t("Run your workflow"))}</b> — ${esc(t("the sample only covers the starter — sign in to run your own graph for real, pay-per-use on your own key."))}`;
     }else if(mode === "shape"){
       txt.innerHTML = `<b>${esc(t("Sample preview"))}</b> — ${esc(t("your edits aren’t reflected yet — results below are still the starter sample. Sign in to run YOUR prompt for real, pay-per-use on your own key."))}`;
+    }else if(mode === "video"){
+      // The motion prompt on an appended video node is always the visitor's own and the clip always
+      // ignores it, so this copy states that outright — the badge alone would be too quiet here.
+      txt.innerHTML = `<b>${esc(t("Sample preview"))}</b> — ${esc(t("the clip below is a canned example of what Image→Video makes, not your prompt. Sign in to run YOUR graph for real, pay-per-use on your own key."))}`;
     }else{
       txt.innerHTML = `<b>${esc(t("Sample run"))}</b> — ${esc(t("results below are canned examples, not live AI — sign in to run it for real, pay-per-use on your own key."))}`;
     }
diff --git a/proof/demo-video/README.md b/proof/demo-video/README.md
new file mode 100644
index 0000000..214afcd
--- /dev/null
+++ b/proof/demo-video/README.md
@@ -0,0 +1,51 @@
+# Signed-out sample run — video result
+
+Proof that a signed-out visitor who adds an Image→Video node to the starter graph gets a real
+video result, and that the run costs nothing.
+
+## Run it
+
+```
+node proof/demo-video/verify-demo-video.mjs
+```
+
+The check is offline and deterministic. It serves the worktree, starts Microsoft Edge in headless
+mode, and drives the real `index.html` through CDP. It blocks the whole `nano-gpt.com` origin, and
+it records each request that the page tries to make. The run must show 36 passed, 0 failed.
+
+The check makes these statements, and it tests each one:
+
+- The starter graph, and the starter graph plus one Image→Video node, are both sample runs.
+- The run-cost chip stays visible in a sample run. It reads `~$X to run for real`.
+- The chip figure increases when the visitor adds the video node. The video node also shows its
+  own price.
+- All 4 nodes finish. The video node output is a `data:video/mp4` URL. The clip decodes to
+  640x360 and 5.04 s.
+- The result carries the `✨ sample result` badge. The ⬇ save and ↗ open buttons are present.
+- The pill says that the clip is a canned example and that it ignores the visitor's prompt.
+- `sw.js` does not precache the clip. The service-worker fetch handler caches it at first use,
+  and the cached bytes are the shipped file.
+- The page calls no billable endpoint. No request reaches `nano-gpt.com`. The sample run finishes
+  with the API unreachable.
+
+## The catalog fixture
+
+`catalog-fixture.json` holds 3 normalized catalog entries: the two models of the starter graph, and
+the model that an appended Image→Video node selects. The check puts them in `localStorage`, because
+the run-cost chip needs prices and the network is off.
+
+To record the fixture again:
+
+```
+node proof/demo-video/verify-demo-video.mjs --capture
+```
+
+This is the only mode that contacts `nano-gpt.com`. It reads the free public model lists
+(`GET /api/v1/{models,image-models,video-models}`) and takes the entries from the app's own
+`localStorage` cache, so the shape cannot differ from the app's normalizers. It never runs a graph,
+and it spends nothing. Prices change, so record the fixture again instead of an edit by hand.
+
+## The clip
+
+`demo-sample.mp4` in the repository root is a real clip. `scripts/gen-demo-clip.mjs` renders it from
+the shipped `demo-sample.jpg` and records the model and the cost.
diff --git a/proof/demo-video/catalog-fixture.json b/proof/demo-video/catalog-fixture.json
new file mode 100644
index 0000000..27364f7
--- /dev/null
+++ b/proof/demo-video/catalog-fixture.json
@@ -0,0 +1,147 @@
+{
+  "note": "Normalized catalog entries for the 3 models the covered demo path uses, read out of the app's own localStorage cache. Re-record with --capture; prices move.",
+  "captured": "2026-07-30",
+  "catalogs": {
+    "chat": [
+      {
+        "id": "zai-org/glm-5.2",
+        "name": "GLM 5.2",
+        "created": 1781481600,
+        "sortUsd": 0.00108,
+        "vision": false,
+        "nsfw": false,
+        "reasoning": true,
+        "structured_output": true,
+        "audio_input": false,
+        "video_input": false,
+        "pdf_upload": false,
+        "maxOut": 131072,
+        "promptUsd1M": 0.42000000000000004,
+        "completionUsd1M": 1.32,
+        "price": "$0.42/$1.32 ·1M"
+      }
+    ],
+    "image": [
+      {
+        "id": "nano-banana-2-lite",
+        "name": "Nano Banana 2 Lite",
+        "created": 1782777600,
+        "sortUsd": 0.04,
+        "edit": true,
+        "gen": true,
+        "inpaint": false,
+        "maxIn": 14,
+        "lora": false,
+        "resolutions": [
+          "1k"
+        ],
+        "maxOut": 4,
+        "fixedCount": 0,
+        "sizePrices": {
+          "1k": 0.04,
+          "auto": 0.04
+        },
+        "nsfw": false,
+        "price": "$0.040/img"
+      }
+    ],
+    "video": [
+      {
+        "id": "google/gemini-omni-flash",
+        "name": "Gemini Omni Flash",
+        "created": 1782777600,
+        "sortUsd": 1.04,
+        "t2v": true,
+        "i2v": true,
+        "v2v": true,
+        "avatar": false,
+        "lora": false,
+        "audioGen": false,
+        "params": {
+          "duration": {
+            "label": "Duration",
+            "description": "Video duration in seconds",
+            "type": "select",
+            "options": [
+              {
+                "value": "3",
+                "label": "3 seconds"
+              },
+              {
+                "value": "4",
+                "label": "4 seconds"
+              },
+              {
+                "value": "5",
+                "label": "5 seconds"
+              },
+              {
+                "value": "6",
+                "label": "6 seconds"
+              },
+              {
+                "value": "7",
+                "label": "7 seconds"
+              },
+              {
+                "value": "8",
+                "label": "8 seconds"
+              },
+              {
+                "value": "9",
+                "label": "9 seconds"
+              },
+              {
+                "value": "10",
+                "label": "10 seconds"
+              }
+            ],
+            "default": "8"
+          },
+          "aspect_ratio": {
+            "label": "Aspect Ratio",
+            "description": "Output aspect ratio",
+            "type": "select",
+            "options": [
+              {
+                "value": "16:9",
+                "label": "Landscape (16:9)"
+              },
+              {
+                "value": "9:16",
+                "label": "Portrait (9:16)"
+              }
+            ],
+            "default": "16:9"
+          }
+        },
+        "defaults": {
+          "duration": "8",
+          "aspect_ratio": "16:9"
+        },
+        "pricing": {
+          "currency": "USD",
+          "per_second_by_mode": {
+            "text_to_video": 0.13,
+            "image_to_video": 0.14,
+            "reference_to_video": 0.16,
+            "video_edit": 0.16
+          },
+          "default_duration": 8,
+          "supported_durations": [
+            3,
+            4,
+            5,
+            6,
+            7,
+            8,
+            9,
+            10
+          ]
+        },
+        "nsfw": false,
+        "price": "~$1.04/clip"
+      }
+    ]
+  }
+}
diff --git a/proof/demo-video/verify-demo-video.mjs b/proof/demo-video/verify-demo-video.mjs
new file mode 100644
index 0000000..2ae4d8a
--- /dev/null
+++ b/proof/demo-video/verify-demo-video.mjs
@@ -0,0 +1,321 @@
+#!/usr/bin/env node
+// Verifies the signed-out sample run reaches a VIDEO result — in real Microsoft Edge, over raw
+// CDP, against the real index.html. Zero API spend, and it proves that rather than assuming it:
+// the whole nano-gpt.com origin is blocked at the network layer AND wrapped by a recording
+// fetch guard, so any request to the API fails the run instead of quietly costing money.
+//
+//   node proof/demo-video/verify-demo-video.mjs             # the check (offline, deterministic)
+//   node proof/demo-video/verify-demo-video.mjs --capture    # refresh catalog-fixture.json
+//   node proof/demo-video/verify-demo-video.mjs --keep-open   # leave the browser up to poke at
+//
+// --capture is the ONLY mode that talks to nano-gpt.com, and only to its free public
+// model-list endpoints (GET /api/v1/{models,image-models,video-models}). It never runs a graph.
+// It re-records catalog-fixture.json: the three normalized catalog entries the covered path
+// needs, taken from the app's own localStorage cache so the shape can never drift from normVideo
+// and friends. Prices move, so re-capture rather than hand-editing the fixture.
+
+import http from "node:http";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import { spawn } from "node:child_process";
+import { fileURLToPath } from "node:url";
+
+const HERE = path.dirname(fileURLToPath(import.meta.url));
+const ROOT = path.dirname(path.dirname(HERE));
+const FIXTURE = path.join(HERE, "catalog-fixture.json");
+const EDGE = "/opt/microsoft/msedge/msedge";
+const CAPTURE = process.argv.includes("--capture");
+const KEEP_OPEN = process.argv.includes("--keep-open");
+
+const MIME = { ".html":"text/html", ".js":"text/javascript", ".mjs":"text/javascript",
+  ".json":"application/json", ".css":"text/css", ".jpg":"image/jpeg", ".jpeg":"image/jpeg",
+  ".png":"image/png", ".mp4":"video/mp4", ".svg":"image/svg+xml", ".ico":"image/x-icon",
+  ".webmanifest":"application/manifest+json", ".txt":"text/plain", ".wav":"audio/wav" };
+
+let pass = 0; const fails = [];
+const ok = (name, cond, detail) => {
+  if (cond) { pass++; console.log(`  ✓ ${name}${detail ? ` — ${detail}` : ""}`); }
+  else { fails.push(name); console.log(`  ✗ ${name}${detail ? ` — ${detail}` : ""}`); }
+};
+const eq = (name, got, want) => ok(name, got === want, `got ${JSON.stringify(got)}, want ${JSON.stringify(want)}`);
+
+/* ---------------- static server (port 0, awaited: no bind race) ---------------- */
+function serve(root) {
+  const srv = http.createServer((req, res) => {
+    let p = decodeURIComponent(req.url.split("?")[0]);
+    if (p === "/") p = "/index.html";
+    const f = path.join(root, p);
+    if (!f.startsWith(root) || !fs.existsSync(f) || fs.statSync(f).isDirectory()) {
+      res.writeHead(404, { "content-type": "text/plain" }); res.end("404"); return;
+    }
+    res.writeHead(200, { "content-type": MIME[path.extname(f).toLowerCase()] || "application/octet-stream" });
+    fs.createReadStream(f).pipe(res);
+  });
+  return new Promise((r) => srv.listen(0, "127.0.0.1", () => r(srv)));
+}
+
+/* ---------------- CDP over the built-in WebSocket (Node 24) ---------------- */
+async function cdp(port) {
+  let info;
+  for (let i = 0; i < 100; i++) {
+    try { info = await (await fetch(`http://127.0.0.1:${port}/json/version`)).json(); break; }
+    catch { await new Promise((r) => setTimeout(r, 100)); }
+  }
+  if (!info) throw new Error("Edge never opened its debug port");
+  const ws = new WebSocket(info.webSocketDebuggerUrl);
+  await new Promise((r, j) => { ws.onopen = r; ws.onerror = j; });
+  let id = 0; const waiting = new Map(); const listeners = [];
+  ws.onmessage = (e) => {
+    const m = JSON.parse(e.data);
+    if (m.id && waiting.has(m.id)) { const { r, j } = waiting.get(m.id); waiting.delete(m.id); m.error ? j(new Error(m.error.message)) : r(m.result); }
+    else if (m.method) listeners.forEach((fn) => fn(m));
+  };
+  const send = (method, params = {}, sessionId) => new Promise((r, j) => {
+    const n = ++id; waiting.set(n, { r, j });
+    ws.send(JSON.stringify({ id: n, method, params, ...(sessionId ? { sessionId } : {}) }));
+  });
+  return { send, on: (fn) => listeners.push(fn), close: () => ws.close() };
+}
+
+/* Evaluate in the page and return the VALUE (throws the page's error, so a typo in a probe
+   fails loudly instead of silently reading as undefined). */
+async function ev(c, sid, expr) {
+  const r = await c.send("Runtime.evaluate", {
+    // async wrapper + awaitPromise so probes may `await` (caches, blobs) as freely as they read DOM
+    expression: `(async()=>{ ${expr} })()`, returnByValue: true, awaitPromise: true, userGesture: true,
+  }, sid);
+  if (r.exceptionDetails) throw new Error("page: " + (r.exceptionDetails.exception?.description || r.exceptionDetails.text));
+  return r.result.value;
+}
+// Poll a condition. Errors count as "not yet": early on, the evaluate races the navigation
+// ("Inspected target navigated or closed") and the app's globals do not exist yet.
+const poll = async (c, sid, expr, ms = 30000, every = 250) => {
+  const t0 = Date.now();
+  for (;;) {
+    try { if (await ev(c, sid, expr)) return true; } catch {}
+    if (Date.now() - t0 > ms) return false;
+    await new Promise((r) => setTimeout(r, every));
+  }
+};
+
+/* ---------------- main ---------------- */
+const srv = await serve(ROOT);
+const base = `http://127.0.0.1:${srv.address().port}`;
+const profile = fs.mkdtempSync(path.join(os.tmpdir(), "nn-demo-video-"));
+const dbg = 9500 + Math.floor(Math.random() * 400);
+const edge = spawn(EDGE, [
+  "--headless=new", `--remote-debugging-port=${dbg}`, `--user-data-dir=${profile}`,
+  "--no-first-run", "--no-default-browser-check", "--disable-gpu", "--mute-audio",
+  "--autoplay-policy=no-user-gesture-required",
+  "--disable-site-isolation-trials",
+  "--disable-features=IsolateOrigins,site-per-process,SitePerProcessOnly",
+  "about:blank",
+], { stdio: "ignore" });
+
+let code = 1;
+try {
+  const c = await cdp(dbg);
+  const { targetId } = await c.send("Target.createTarget", { url: "about:blank" });
+  const { sessionId: sid } = await c.send("Target.attachToTarget", { targetId, flatten: true });
+  await c.send("Page.enable", {}, sid);
+  await c.send("Runtime.enable", {}, sid);
+  await c.send("Network.enable", {}, sid);
+
+  // Every nano-gpt.com request the page attempts, recorded from OUTSIDE the page.
+  const apiHits = [];
+  c.on((m) => {
+    if (m.method === "Network.requestWillBeSent" && /nano-gpt\.com/.test(m.params.request.url)) apiHits.push(m.params.request.url);
+  });
+  if (!CAPTURE) await c.send("Network.setBlockedURLs", { urls: ["*nano-gpt.com*"] }, sid);
+
+  const fixture = (!CAPTURE && fs.existsSync(FIXTURE)) ? JSON.parse(fs.readFileSync(FIXTURE, "utf8")) : null;
+  if (!CAPTURE && !fixture) throw new Error(`no ${FIXTURE} — run with --capture once`);
+
+  // Signed OUT, welcome dismissed, catalogs primed from the fixture (so prices exist with the
+  // network off), plus an in-page fetch guard that records and refuses the API either way.
+  await c.send("Page.addScriptToEvaluateOnNewDocument", { source: `
+    try {
+      localStorage.clear();
+      localStorage.setItem("noodle_welcome_seen", "1");
+      localStorage.setItem("noodle_make_cta_shown", "1");
+      ${fixture ? Object.entries(fixture.catalogs).map(([k, list]) =>
+        `localStorage.setItem("nn_catalog_${k}", JSON.stringify({ t: Date.now(), list: ${JSON.stringify(list)} }));`).join("\n      ") : ""}
+    } catch (e) {}
+    window.__apiHits = [];
+    const _f = window.fetch;
+    window.fetch = function (u, o) {
+      const url = String((u && u.url) || u);
+      if (url.includes("nano-gpt.com")) {
+        window.__apiHits.push(url);
+        ${CAPTURE ? "return _f.apply(this, arguments);" : 'return Promise.reject(new Error("BLOCKED by the harness: " + url));'}
+      }
+      return _f.apply(this, arguments);
+    };
+  ` }, sid);
+
+  await c.send("Page.navigate", { url: base + "/index.html" }, sid);
+
+  console.log(CAPTURE ? "\n== capturing catalog fixture ==" : "\n== signed-out demo run reaches a video result ==");
+
+  // Boot: the classic (non-module) script means the app's own functions are real globals.
+  if (!await poll(c, sid, `return typeof demoMode === "function" && typeof addNode === "function" && graph.nodes.length === 3;`, 20000))
+    throw new Error("app never booted (3 starter nodes + demoMode)");
+
+  if (CAPTURE) {
+    if (!await poll(c, sid, `return !!(catalogs.chat && catalogs.chat.length && catalogs.image && catalogs.image.length && catalogs.video && catalogs.video.length);`, 30000))
+      throw new Error("live catalogs never arrived");
+    const cap = await ev(c, sid, `
+      const want = defModelFor("ivideo");                                 // the app's OWN resolver — the fixture must hold the model a real appended node gets
+      const vid = catalogs.video.find(m => m.id === want);
+      return { chat: catalogs.chat.filter(m => m.id === "zai-org/glm-5.2"),
+               image: catalogs.image.filter(m => m.id === "nano-banana-2-lite"),
+               video: vid ? [vid] : [] };
+    `);
+    for (const k of ["chat", "image", "video"]) if (!cap[k].length) throw new Error(`capture: no ${k} entry found`);
+    fs.writeFileSync(FIXTURE, JSON.stringify({
+      note: "Normalized catalog entries for the 3 models the covered demo path uses, read out of the app's own localStorage cache. Re-record with --capture; prices move.",
+      captured: new Date().toISOString().slice(0, 10), catalogs: cap,
+    }, null, 2) + "\n");
+    console.log(`  wrote ${path.relative(ROOT, FIXTURE)} — video model ${cap.video[0].id}`);
+    code = 0;
+  } else {
+    const chip = `(()=>{ const e=document.getElementById("runest"); return { hidden:e.hidden, display:getComputedStyle(e).display, text:e.textContent.trim(), title:e.title }; })()`;
+
+    // ---- 1. the pristine starter still samples, and still prices itself ----
+    eq("starter demoMode is a sampleable mode", await ev(c, sid, `return demoMode();`), "exact");
+    eq("signed out", await ev(c, sid, `return !getKey();`), true);
+    let ch = await ev(c, sid, `return ${chip};`);
+    ok("starter: run-cost chip VISIBLE in demo mode", ch.display !== "none" && !ch.hidden, `display=${ch.display}`);
+    ok("starter: chip says the price is for the real run", /to run for real/.test(ch.text), JSON.stringify(ch.text));
+    ok("starter: chip title says this run is not billed", /isn’t billed/.test(ch.title), JSON.stringify(ch.title.split("\n")[0]));
+    ok("starter: chip shows a real dollar figure", /\$\d/.test(ch.text) || /<\$0\.01/.test(ch.text), JSON.stringify(ch.text));
+
+    // ---- 2. append the covered Image→Video node with the app's own API ----
+    const vid = await ev(c, sid, `
+      const img = graph.nodes.find(n => n.type === "image");
+      const v = addNode("ivideo", img.x + 300, img.y);
+      connect(img.id, "image", v.id, "image");
+      refreshAllPrices();
+      return { id: v.id, model: v.fields.model, nodes: graph.nodes.length };
+    `);
+    eq("Image→Video node appended", vid.nodes, 4);
+    ok("it picked a real i2v model", !!vid.model, vid.model);
+    eq("demoMode() is now 'video'", await ev(c, sid, `return demoMode();`), "video");
+    eq("demoVideoNode() returns THAT node", await ev(c, sid, `const v = demoVideoNode(); return v && v.id;`), vid.id);
+    eq("still a demo run", await ev(c, sid, `return inDemoRun();`), true);
+
+    // ---- 3. the price disclosure survives the priciest node (the review finding) ----
+    const before = ch;
+    ch = await ev(c, sid, `return ${chip};`);
+    ok("video node: run-cost chip STILL VISIBLE", ch.display !== "none" && !ch.hidden, `display=${ch.display}, text=${JSON.stringify(ch.text)}`);
+    ok("video node: chip still labelled for the real run", /to run for real/.test(ch.text), JSON.stringify(ch.text));
+    const usd = (s) => { const m = s.match(/\$([\d.]+)/); return m ? parseFloat(m[1]) : 0; };
+    ok("adding the video node RAISED the quoted price", usd(ch.text) > usd(before.text), `${before.text.trim()} → ${ch.text.trim()}`);
+    ok("the video node shows its own per-run price too", await ev(c, sid, `
+      const v = byId(${JSON.stringify(vid.id)}); const el = v.el.querySelector("[data-mp]");
+      return !!(el && /\\$/.test(el.textContent));
+    `), await ev(c, sid, `return byId(${JSON.stringify(vid.id)}).el.querySelector("[data-mp]").textContent.trim();`));
+
+    // ---- 4. run it, signed out, with the service worker in charge ----
+    // The clip is deliberately absent from sw.js's SHELL precache list, so the ONLY thing that
+    // ever caches it is the fetch handler, on first use. Wait until the SW actually controls the
+    // page before running, otherwise that path is never exercised and the assert below is a lie.
+    const swReady = await poll(c, sid, `return !!navigator.serviceWorker.controller;`, 20000);
+    ok("a service worker controls the page", swReady, swReady ? "controller present" : "no controller in 20 s");
+    eq("the clip is NOT precached (not in SHELL)", await ev(c, sid, `
+      return await (await caches.open("nanoodle-v6")).match("/demo-sample.mp4") ? "cached" : "absent";
+    `), "absent");
+
+    await ev(c, sid, `document.getElementById("run").click(); return 1;`);
+    const done = await poll(c, sid,
+      `return graph.nodes.filter(n => n.el && n.el.dataset.status === "done").length === 4;`, 60000);
+    const statuses = await ev(c, sid, `return graph.nodes.map(n => n.type + ":" + (n.el && n.el.dataset.status));`);
+    ok("all 4 nodes reached done", done, statuses.join(", "));
+
+    // ---- 5. it is really a video, and really the shipped clip ----
+    const out = await ev(c, sid, `
+      const v = byId(${JSON.stringify(vid.id)});
+      const el = v.el.querySelector(".result video");
+      return { url: (v.out && v.out.video || "").slice(0, 24), len: (v.out && v.out.video || "").length,
+        hasEl: !!el, srcMatches: !!el && el.src === v.out.video,
+        readyState: el ? el.readyState : -1, duration: el ? el.duration : -1,
+        w: el ? el.videoWidth : -1, h: el ? el.videoHeight : -1,
+        badge: (v.el.querySelector(".demobadge") || {}).textContent || "",
+        save: !!v.el.querySelector(".result [data-dl]"), open: !!v.el.querySelector(".result [data-open]") };
+    `);
+    ok("video output is a data:video/mp4 URL", out.url.startsWith("data:video/mp4"), `${out.url}… (${out.len} chars)`);
+    ok("a <video> element renders it", out.hasEl && out.srcMatches, `hasEl=${out.hasEl} srcMatches=${out.srcMatches}`);
+    eq("the clip actually decoded (readyState 4)", out.readyState, 4);
+    ok("duration is the shipped clip's 5.04 s", Math.abs(out.duration - 5.041667) < 0.05, String(out.duration));
+    ok("dimensions are the shipped clip's 640x360", out.w === 640 && out.h === 360, `${out.w}x${out.h}`);
+    ok("carries the ✨ sample result badge", /✨/.test(out.badge) && /sample result/.test(out.badge), JSON.stringify(out.badge));
+    ok("⬇ save and ↗ open are offered, like a real result", out.save && out.open, `save=${out.save} open=${out.open}`);
+
+    // ---- 5b. …and the service worker cached it on that first use ----
+    ok("the fetch handler cached the clip on first use", await poll(c, sid, `
+      const r = await (await caches.open("nanoodle-v6")).match("/demo-sample.mp4");
+      return !!r && r.ok;
+    `, 10000), "present in nanoodle-v6 after the run");
+    eq("what it cached is the real clip, byte for byte", await ev(c, sid, `
+      const r = await (await caches.open("nanoodle-v6")).match("/demo-sample.mp4");
+      const b = await r.blob();
+      return b.size + " " + b.type;
+    `), "228408 video/mp4");
+
+    // ---- 6. the pill tells the truth about whose prompt made the clip ----
+    const pill = await ev(c, sid, `
+      const p = document.getElementById("demopop");
+      return { shown: !!p && getComputedStyle(p).display !== "none", text: p ? p.textContent : "" };
+    `);
+    ok("the demo pill is up", pill.shown, `display checked`);
+    ok("pill says the clip is canned and ignores the visitor's prompt",
+      /canned example of what Image→Video makes, not your prompt/.test(pill.text), JSON.stringify(pill.text.slice(0, 120)));
+
+    // ---- 7. every other result still carries its badge ----
+    eq("all 3 output nodes are badged", await ev(c, sid, `return document.querySelectorAll(".demobadge").length;`), 3);
+
+    // ---- 8. and it cost nothing, provably ----
+    // The only nano-gpt.com URLs the page may even ATTEMPT are the free, read-only model lists
+    // (the boot SWR revalidate). Anything else is a billable endpoint and fails the run. Here
+    // even the lists were blocked, and the run still finished — the demo path is fully offline.
+    const inPage = await ev(c, sid, `return window.__apiHits.slice();`);
+    const CATALOG_ONLY = /^https:\/\/nano-gpt\.com\/api\/v1\/(models\?detailed=true|image-models|video-models|audio-models)$/;
+    const billable = inPage.filter((u) => !CATALOG_ONLY.test(u));
+    ok("no billable NanoGPT endpoint was called", billable.length === 0, billable.join(", ") || `0 (only ${inPage.length} free model-list reads, all blocked)`);
+    ok("no nano-gpt.com request left the browser", apiHits.length === 0, apiHits.join(", ") || "0 requests");
+    ok("the whole sample run works with nano-gpt.com unreachable", done, "4/4 nodes done, network blocked");
+
+    // ---- 9. the sign-in wall still guards everything not covered ----
+    eq("a 2nd video node loses demo mode (wall)", await ev(c, sid, `
+      const img = graph.nodes.find(n => n.type === "image");
+      const v2 = addNode("ivideo", img.x + 300, img.y + 260);
+      connect(img.id, "image", v2.id, "image");
+      const m = demoMode();
+      graph.nodes.pop(); graph.links.pop();
+      return m;
+    `), null);
+    eq("a node downstream of the clip loses demo mode (wall)", await ev(c, sid, `
+      const v = byId(${JSON.stringify(vid.id)});
+      const e = addNode("vedit", v.x + 300, v.y);
+      connect(v.id, "video", e.id, "video");
+      const m = demoMode();
+      graph.nodes.pop(); graph.links.pop();
+      return m;
+    `), null);
+    eq("back to 'video' once the canvas is the covered shape again", await ev(c, sid, `return demoMode();`), "video");
+
+    console.log(`\n${fails.length ? "✗" : "✓"} ${pass} passed, ${fails.length} failed` + (fails.length ? `\n  ${fails.join("\n  ")}` : ""));
+    code = fails.length ? 1 : 0;
+  }
+
+  if (KEEP_OPEN) { console.log(`\nbrowser left open on ${base} (debug :${dbg}) — ctrl-C to stop`); await new Promise(() => {}); }
+  c.close();
+} catch (e) {
+  console.error("✗ harness error: " + e.message);
+} finally {
+  if (edge.pid) { try { process.kill(edge.pid, "SIGTERM"); } catch {} }   // exact PID, never a pattern kill
+  srv.close();
+  try { fs.rmSync(profile, { recursive: true, force: true }); } catch {}
+}
+process.exit(code);
diff --git a/scripts/gen-demo-clip.mjs b/scripts/gen-demo-clip.mjs
new file mode 100644
index 0000000..2f4e134
--- /dev/null
+++ b/scripts/gen-demo-clip.mjs
@@ -0,0 +1,178 @@
+#!/usr/bin/env node
+/**
+ * gen-demo-clip.mjs — render the signed-out sample clip (demo-sample.mp4).
+ *
+ * WHY THIS EXISTS
+ * ---------------
+ * A signed-out visitor can Run the starter graph and see real canned results (DEMO_LLM_TEXT +
+ * demo-sample.jpg). index.html also covers ONE extension of that graph: an 📽️ Image→Video node
+ * hung off the image output. That node serves demo-sample.mp4.
+ *
+ * The clip has to be an HONEST sample. It is a real image→video generation from the SHIPPED
+ * demo-sample.jpg, not a pan-and-scan of the still. This script is how it was made, so the asset
+ * is reproducible and its provenance lives in the repo.
+ *
+ * THIS SCRIPT SPENDS REAL MONEY. It is hand-run only. No hook, no CI job calls it.
+ * At the defaults below the generation costs about 0.12 USD.
+ *
+ * USAGE
+ *   NANOGPT_API_KEY=... node scripts/gen-demo-clip.mjs            # dry run: prints the plan + price
+ *   NANOGPT_API_KEY=... node scripts/gen-demo-clip.mjs --yes      # generate, encode, write the file
+ *
+ * OPTIONS (env)
+ *   MODEL       video model id            (default below)
+ *   RESOLUTION  480p | 720p | 1080p       (default below)
+ *   DURATION    seconds, 2..12            (default below)
+ *   KEEP_RAW=1  also keep the provider's original download next to the encoded file
+ *
+ * PROVENANCE OF THE COMMITTED FILE
+ *   model       bytedance-seedance-v1-pro-fast (SeeDance V1 Pro Fast)
+ *   source      demo-sample.jpg (the shipped still, unmodified — frame 0 of the clip IS that still)
+ *   settings    720p, 5s, 16:9
+ *   cost        0.12 USD, metered by NanoGPT on 2026-07-28 (runId vid_ms5jr1es67cfaa050a06)
+ *   encode      H.264 High, no audio track, faststart (see FFMPEG_ARGS)
+ *   result      640x360, 24 fps, 5.04 s, 223 KB (2828 KB before the encode)
+ *
+ * OUTPUT SIZE
+ *   Signed-out visitors fetch this file, so keep it well under 2 MB. The ffmpeg step below
+ *   re-encodes to 640px wide at CRF 30 and the script REFUSES to write a file over SIZE_CAP.
+ *   If a future model returns something bigger, lower the width or raise the CRF — do not raise
+ *   the cap.
+ */
+
+import { execFileSync } from "node:child_process";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+
+const ROOT = path.dirname(path.dirname(fileURLToPath(import.meta.url)));
+const SRC_IMAGE = path.join(ROOT, "demo-sample.jpg");
+const OUT_CLIP = path.join(ROOT, "demo-sample.mp4");
+
+const NANOGPT = "https://nano-gpt.com";
+const MODEL = process.env.MODEL || "bytedance-seedance-v1-pro-fast";
+const RESOLUTION = process.env.RESOLUTION || "720p";
+const DURATION = process.env.DURATION || "5";
+const ASPECT = "16:9";
+const SIZE_CAP = 2 * 1024 * 1024;          // 2 MB — the honest ceiling for an asset every visitor may fetch
+const POLL_MS = 5000;
+const POLL_LIMIT = 180;                    // 15 minutes, then give up rather than poll forever
+
+// The motion the still cannot show. Deliberately gentle: the sample must read as "the shop is
+// alive", not as a different scene, because the visitor sees the still one node upstream.
+const PROMPT = "Gentle cinematic push-in on the ramen shop window. Steam rises and curls from the "
+  + "bowl. Rain streaks down the glass and ripples the puddles. The lanterns and neon signs flicker "
+  + "softly. Subtle handheld drift, no cuts, no camera whip.";
+
+// 640px wide keeps the node preview crisp and the file small. No audio track: the sample models
+// used here render silent clips, and a silent track would only add bytes.
+const FFMPEG_ARGS = (input, output) => ([
+  "-y", "-i", input,
+  "-an",
+  "-vf", "scale=640:-2:flags=lanczos",
+  "-c:v", "libx264", "-profile:v", "high", "-preset", "slow", "-crf", "30",
+  "-pix_fmt", "yuv420p", "-movflags", "+faststart",
+  output,
+]);
+
+const die = (msg) => { console.error("✗ " + msg); process.exit(1); };
+const sleep = (ms) => new Promise((r) => setTimeout(r, ms));
+
+const KEY = process.env.NANOGPT_API_KEY;
+if (!KEY) die("NANOGPT_API_KEY is not set");
+if (!fs.existsSync(SRC_IMAGE)) die(`missing source still: ${SRC_IMAGE}`);
+
+// Catalog price for the exact settings, so the operator sees the bill before agreeing to it.
+async function quote() {
+  const r = await fetch(`${NANOGPT}/api/v1/video-models`, { headers: { Authorization: "Bearer " + KEY } });
+  if (!r.ok) return null;
+  const m = ((await r.json()).data || []).find((x) => x.id === MODEL);
+  const per = m?.pricing?.per_second_by_resolution?.[RESOLUTION];
+  return (per == null) ? null : per * Number(DURATION);
+}
+
+const est = await quote();
+console.log(`model       ${MODEL}`);
+console.log(`source      ${path.relative(ROOT, SRC_IMAGE)}`);
+console.log(`settings    ${RESOLUTION}, ${DURATION}s, ${ASPECT}`);
+console.log(`estimate    ${est == null ? "unknown (model not in the catalog)" : "$" + est.toFixed(3)}`);
+console.log(`output      ${path.relative(ROOT, OUT_CLIP)} (cap ${(SIZE_CAP / 1024 / 1024).toFixed(0)} MB)`);
+
+if (!process.argv.includes("--yes")) {
+  console.log("\ndry run — re-run with --yes to spend and write the file.");
+  process.exit(0);
+}
+
+// ---- 1. submit ------------------------------------------------------------
+const b64 = fs.readFileSync(SRC_IMAGE).toString("base64");
+const body = {
+  model: MODEL,
+  prompt: PROMPT,
+  imageDataUrl: `data:image/jpeg;base64,${b64}`,
+  resolution: RESOLUTION,
+  duration: DURATION,
+  aspect_ratio: ASPECT,
+};
+console.log("\n→ submitting…");
+const sub = await fetch(`${NANOGPT}/api/generate-video`, {
+  method: "POST",
+  headers: { Authorization: "Bearer " + KEY, "Content-Type": "application/json" },
+  body: JSON.stringify(body),
+});
+const subText = await sub.text();
+if (!sub.ok) die(`submit failed ${sub.status}: ${subText.slice(0, 500)}`);
+const subJson = JSON.parse(subText);
+const runId = subJson.runId || subJson.id;
+if (!runId) die(`no runId in the reply: ${subText.slice(0, 500)}`);
+console.log(`  runId ${runId}`);
+
+// ---- 2. poll --------------------------------------------------------------
+let out = null, cost = subJson.cost ?? null;
+for (let i = 0; i < POLL_LIMIT; i++) {
+  await sleep(POLL_MS);
+  let s;
+  try {
+    s = await (await fetch(`${NANOGPT}/api/video/status?requestId=${encodeURIComponent(runId)}`,
+      { headers: { Authorization: "Bearer " + KEY } })).json();
+  } catch { continue; }
+  const st = String(s.data?.status || s.status || "").toUpperCase();
+  process.stdout.write(`\r  ${st} ${(i + 1) * POLL_MS / 1000}s   `);
+  if (s.cost != null) cost = s.cost;
+  if (s.data?.cost != null) cost = s.data.cost;
+  if (st === "COMPLETED" || st === "SUCCEEDED") {
+    const o = s.data?.output || s.output || {};
+    out = o.video?.url || o.url || (Array.isArray(o.video) ? o.video[0]?.url : null);
+    break;
+  }
+  if (st === "FAILED" || st === "ERROR" || st === "CANCELLED") die(`\njob ${st}: ${JSON.stringify(s).slice(0, 500)}`);
+}
+console.log("");
+if (!out) die("no video URL — the job never completed. The charge (if any) already happened; do NOT re-run blindly.");
+console.log(`  url ${out}`);
+console.log(`  cost ${cost == null ? "not reported by the API — read it off the NanoGPT balance" : "$" + Number(cost).toFixed(4)}`);
+
+// ---- 3. download ----------------------------------------------------------
+const raw = path.join(fs.mkdtempSync(path.join(os.tmpdir(), "demo-clip-")), "raw.mp4");
+const dl = await fetch(out);
+if (!dl.ok) die(`download failed ${dl.status}`);
+fs.writeFileSync(raw, Buffer.from(await dl.arrayBuffer()));
+console.log(`  raw ${(fs.statSync(raw).size / 1024).toFixed(0)} KB → ${raw}`);
+
+// ---- 4. encode small ------------------------------------------------------
+try { execFileSync("ffmpeg", FFMPEG_ARGS(raw, OUT_CLIP), { stdio: ["ignore", "ignore", "pipe"] }); }
+catch (e) { die(`ffmpeg failed: ${String(e.stderr || e).slice(0, 500)}`); }
+
+const size = fs.statSync(OUT_CLIP).size;
+if (size > SIZE_CAP) {
+  fs.unlinkSync(OUT_CLIP);
+  die(`encoded file is ${(size / 1024 / 1024).toFixed(2)} MB, over the ${(SIZE_CAP / 1024 / 1024).toFixed(0)} MB cap — `
+    + "lower the scale width or raise the CRF in FFMPEG_ARGS and re-encode the raw file. Do not raise the cap.");
+}
+if (process.env.KEEP_RAW === "1") {
+  const keep = OUT_CLIP.replace(/\.mp4$/, ".raw.mp4");
+  fs.copyFileSync(raw, keep);
+  console.log(`  kept raw at ${path.relative(ROOT, keep)} (do NOT commit it)`);
+}
+console.log(`\n✓ wrote ${path.relative(ROOT, OUT_CLIP)} — ${(size / 1024).toFixed(0)} KB`);
+console.log("  Update the PROVENANCE block at the top of this file with the model, settings and real cost.");
diff --git a/sw.js b/sw.js
index 2084ab1..679d836 100644
--- a/sw.js
+++ b/sw.js
@@ -2,6 +2,10 @@
 // Network-first for same-origin GETs (so new deploys always show when online),
 // cache fallback when offline. Cross-origin requests (the NanoGPT API) are never touched.
 const CACHE = "nanoodle-v6"; // bump this version on every release to purge stale offline caches
+// demo-sample.mp4 is deliberately NOT here. It is the signed-out sample clip, ~220 KB, and only
+// one path needs it (the starter plus an Image→Video node). Precaching it would cost every install
+// 4x the whole rest of this list for a screen most visitors never open. The fetch handler below
+// caches it on first use instead, and index.html degrades to the sign-in wall when it is missing.
 const SHELL = [
   "/", "/index.html", "/play", "/legal", "/site.webmanifest", "/noodle-graph.json", "/demo-sample.jpg",
   "/favicon.ico", "/favicon-16.png", "/favicon-32.png", "/apple-touch-icon.png", "/icon-192.png", "/icon-512.png",